a.java

 @Test
    public void test() {
        JSONObject root = new JSONObject("{}");
        List<TestC> list = new ArrayList<>();
        TestC testC = new TestC("type", "bucket", "code", null, DateTime.now(),
            null);
        TestC testC1 = new TestC("type", "bucket", "code", null, DateTime.now(),
            null);

        root.put("1", testC);

        list.add(testC);
        list.add(testC1);

        root.put("2", list);
    }

    private static class TestC {
        private final String type;
        private final String bucket;
        private final String code;
        private final Object o;
        private final DateTime now;
        private final Object o1;

        public TestC(String type, String bucket, String code, Object o, DateTime now, Object o1) {

            this.type = type;
            this.bucket = bucket;
            this.code = code;
            this.o = o;
            this.now = now;
            this.o1 = o1;
        }
    }